1. Field of the Invention
The present invention relates to a flat panel display device, and more particularly to an apparatus for fabricating a flat panel display device, a method of fabricating the same, and a method of fabricating a flat panel display device using the same. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for simplifying a fabrication process of the flat panel display device by using a soft mold rather than a photolithography process to form a thin film pattern.
2. Description of the Related Art
In the current information-driven society, display devices have grown in importance because of the pervasiveness of visual information as a medium of communication. In this respect, cathode ray tubes (CRT) or Braun tubes, which have been at the mainstream of visual displays, have become less appealing because they are heavy and bulky.
Flat panel display devices, such as liquid crystal display LCD, field emission display FED, plasma display panel PDP, organic light emitting diode OLED, etc., have been introduced as alternatives to CRTs for integration in new electrical appliances because they are light, thin, small and short. Recent breakthroughs in research and development have lead to improvement in the mass productivity of these flat panel display devices to a point where the flat panel display devices have become viable replacement to CRTs in many fields of application.
The recent improvement in the mass production of flat panel display devices has particularly lead to the rapid development of large and high-resolution active matrix type liquid crystal display devices. Active matrix LCD devices provide good picture quality and consume little power. In an active matrix LCD device, a thin film transistor (“TFT”) is used to drive a liquid crystal cell.
FIG. 1 is an exploded perspective view of a portion of an active matrix type liquid crystal display device in accordance with the related art. Referring to FIG. 1, the active matrix type LCD device has a color filter substrate 22 and a TFT array substrate 23 bonded with a liquid crystal layer 15 therebetween. The color filter substrate 22 includes an upper glass substrate 12, a color filter 13 and a common electrode 14 formed on a rear surface of the upper glass substrate 12. The color filter 13 has a color filter layer of red (R), green (G), blue (B) disposed to transmit a light of a specific range of wavelengths to display color images. A black matrix (not shown) is formed between the color filters 13 of adjacent R, G, and B colors. Alignment films (not shown) are formed on surfaces of the color filter substrate 22 and the array TFT substrate 23 facing the liquid crystal layer 15.
The TFT array substrate 23 includes a lower glass substrate 16. Data lines 19 and gate lines 18 cross each other to define cell areas in the front surface of the lower glass substrate 16. A pixel electrode 21 is formed at each of the cell areas defined the data line 19 and the gate line 18. TFTs 20 are formed at the crossings of the data lines 19 and the gate lines 18 in each of the cell areas. Each of the TFT 20 switches a data transmission path between the data line 19 and the pixel electrode 21 in response to a scan signal from the gate line 18, thereby driving the pixel electrode 21. An electric field is applied to the liquid crystal 15 to control the transmittance of light incident through the TFT array substrate 23.
A polarizer 11 is attached to a front surface of the upper glass substrate 12. A polarizer 17 is also attached to the rear surface of the lower glass substrate 16. The polarizers 17 and 11 polarize light for transmission in one direction onto the rear surface of the lower glass substrate 16 and the out of the front surface of the color filter substrate 22, respectively. In a TN mode LCD device, the polarizing directions of polarizers 11 and 17 cross each other at a 90° angle.
The fabrication of the active matrix type liquid crystal display device can be divided into substrate cleaning process, a substrate patterning process, a alignment film forming/rubbing process, a substrate bonding/liquid crystal injecting process, a mounting process, an inspection process, a repairing process, etc. In the substrate cleaning process, a cleaning solution is used to remove impurities contaminating the substrate surface of the LCD device. The substrate patterning process includes a color filter substrate patterning process and a TFT-array substrate patterning process. In the alignment film forming/rubbing process, an alignment film is spread over each of the color filter substrate and the TFT array substrate, and the alignment film is rubbed with a rubbing cloth, etc. In the substrate bonding/liquid crystal injecting process, a sealant is used to bond the color filter substrate 22 and the TFT array substrate 23, and a liquid crystal and a spacer are injected through a liquid crystal injection hole, and then a process of sealing the liquid crystal injection hole is performed. In the mounting process, a tape carrier package (hereinafter, referred to as “TCP”), on which an integrated circuit such as a gate drive integrated circuit or a data drive integrated circuit is mounted, is connected to a pad part on the substrate. The drive integrated circuit can also be directly mounted on the substrate by a chip-on-glass (hereinafter, referred to as “COG”) method other than a tape automated bonding method using the foregoing TCP. The inspecting process includes an electrical inspection performed after forming the pixel electrode and the signal lines such as the data line and the gate line in the TFT array substrate; an electrical inspection performed after the substrate bonding/liquid crystal injecting process; and a macrography. The repairing process performs restoration for the substrate which is found repairable in the inspecting process. On the other hand, defect substrates which are found un-repairable in the inspecting process are disposed off as waste.
In the related art fabricating method of most flat panel display devices, including LCD devices, a thin film material deposited on the substrate is patterned by a photolithography process. The photolithography process involves a series of photo-processes including a photo-resist spreading process, a mask aligning process, an exposing process, a developing process and a cleaning process. However, the photolithography process requires a long time for completion, uses large amounts of photo-resist material and stripping solution, and requires expensive equipments, such as exposure equipment, etc. Thus, there is a need for a simpler thin film patterning process for the flat panel display device, which is faster, less wasteful, and cheaper than the related art photolithography process.